198 lines
7.6 KiB
Python
198 lines
7.6 KiB
Python
from typing import Dict, List, Tuple
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from cacheflow.master.block_manager import BlockSpaceManager
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from cacheflow.sequence import Sequence
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from cacheflow.sequence import SequenceGroup
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from cacheflow.sequence import SequenceStatus
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class Scheduler:
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def __int__(
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self,
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controllers: List,
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block_size: int,
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num_gpu_blocks: int,
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num_cpu_blocks: int,
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) -> None:
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self.controllers = controllers
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self.block_size = block_size
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self.num_gpu_blocks = num_gpu_blocks
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self.num_cpu_blocks = num_cpu_blocks
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# Create the block space manager.
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self.block_manager = BlockSpaceManager(
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block_size=block_size,
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num_gpu_blocks=num_gpu_blocks,
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num_cpu_blocks=num_cpu_blocks,
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)
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# Serving sequence groups (FIFO).
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self.serving: List[SequenceGroup] = []
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# Mapping: group_id -> num_steps.
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self.num_steps: Dict[int, int] = {}
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# Mapping: group_id -> max_num_steps.
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self.max_num_steps: Dict[int, int] = {}
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# Mapping: group_id -> stop_token_ids.
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self.stop_token_ids: Dict[int, List[int]] = {}
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# Swapped sequence groups (LIFO).
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self.swapped: List[SequenceGroup] = []
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# Pending sequence groups (FIFO).
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self.pending: List[SequenceGroup] = []
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# Blocks that need to be swaped or copied before model execution.
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self.blocks_to_swap_in: Dict[int, int] = []
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self.blocks_to_swap_out: Dict[int, int] = []
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self.blocks_to_copy: Dict[int, int] = []
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def _free_seq(self, seq: Sequence) -> None:
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seq.status = SequenceStatus.FINISHED
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self.block_manager.free(seq)
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def _allocate(self, seq_group: SequenceGroup) -> None:
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self.block_manager.allocate(seq_group)
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for seq in seq_group.seqs:
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seq.status = SequenceStatus.RUNNING
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self.serving.append(seq_group)
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def _append(self, seq_group: SequenceGroup) -> None:
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for seq in seq_group.seqs:
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if seq.status == SequenceStatus.FINISHED:
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continue
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ret = self.block_manager.append(seq)
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if ret is not None:
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src_block, dst_block = ret
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self.blocks_to_copy[src_block] = dst_block
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def _swap_in(self, seq_group: SequenceGroup) -> None:
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mapping = self.block_manager.swap_in(seq_group)
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self.blocks_to_swap_in.update(mapping)
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for seq in seq_group.seqs:
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if seq.status == SequenceStatus.SWAPPED:
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seq.status = SequenceStatus.RUNNING
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self.serving.append(seq_group)
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def _swap_out(self, seq_group: SequenceGroup) -> None:
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assert self.block_manager.can_swap_out(seq_group)
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mapping = self.block_manager.swap_out(seq_group)
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self.blocks_to_swap_out.update(mapping)
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for seq in seq_group.seqs:
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if seq.status == SequenceStatus.RUNNING:
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seq.status = SequenceStatus.SWAPPED
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self.swapped.append(seq_group)
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def prepare(self) -> None:
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# 1. Prepare new slots for the running sequences.
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# NOTE: Here we implicitly assume FCFS scheduling.
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# That is, the most recently added sequence group is the first
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# to be swapped out.
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victim_idx = len(self.serving) - 1
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for i, seq_group in enumerate(self.serving):
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if i > victim_idx:
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# The i-th sequence group has already been swapped out.
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break
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# OOM. Swap out the victim sequence groups.
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while not self.block_manager.can_append(seq_group):
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victim_seq_group = self.serving[victim_idx]
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self._swap_out(victim_seq_group)
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victim_idx -= 1
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if i > victim_idx:
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# No other sequence groups can be swapped out.
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break
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else:
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self._append(seq_group)
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self.serving = self.serving[:victim_idx + 1]
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# 2. Swap in the swapped sequences if possible.
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# NOTE: Here we implicitly assume FCFS scheduling.
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# The swapped sequences are in LIFO order.
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for i, seq_group in enumerate(reversed(self.swapped)):
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if self.block_manager.can_swap_in(seq_group):
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self._swap_in(seq_group)
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self._append(seq_group)
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else:
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# OOM. Stop swapping.
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self.swapped = self.swapped[:len(self.swapped) - i]
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break
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else:
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# All swapped sequences are swapped in.
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self.swapped.clear()
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# 3. Join new sequences if possible.
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# NOTE: Here we implicitly assume FCFS scheduling.
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# TODO(woosuk): Add a heuristic to control the maximum batch size.
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if not self.swapped:
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for i, seq_group in enumerate(self.pending):
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if self.block_manager.can_allocate(seq_group):
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self._allocate(seq_group)
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else:
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# FIXME: Consider the race condition.
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self.pending = self.pending[i:]
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break
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def step(self) -> None:
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# Ensure that either swap-in or swap-out is performed.
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if self.blocks_to_swap_in is not None:
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assert self.blocks_to_swap_out is None
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# Execute the first stage of the pipeline.
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self.controllers[0].execute_stage(
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self.blocks_to_swap_in.copy(),
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self.blocks_to_swap_out.copy(),
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self.blocks_to_copy.copy(),
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)
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# Clear for the next step.
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self.blocks_to_swap_in.clear()
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self.blocks_to_swap_out.clear()
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self.blocks_to_copy.clear()
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def post_step(
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self,
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next_tokens: Dict[int, Tuple[int, int]],
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) -> None:
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# Update the running sequences and free blocks.
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for seq_group in self.serving:
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group_id = seq_group.group_id
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self.num_steps[group_id] += 1
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stop_token_ids = self.stop_token_ids[group_id]
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for seq in seq_group.seqs:
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if seq.status == SequenceStatus.FINISHED:
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continue
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parent_seq_id, next_token = next_tokens[seq.seq_id]
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if seq.seq_id != parent_seq_id:
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# The sequence is a fork of the parent sequence (beam search).
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# Free the current sequence.
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self.block_manager.free(seq)
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# Fork the parent sequence.
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parent_seq = seq_group.find(parent_seq_id)
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seq.logical_token_blocks = parent_seq.logical_token_blocks.copy()
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self.block_manager.fork(parent_seq, seq)
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# Append a new token to the sequence.
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seq.append(next_token)
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# Check if the sequence has generated a stop token.
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if next_token in stop_token_ids:
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self._free_seq(seq)
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continue
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# Check if the sequence has reached the maximum number of steps.
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if self.num_steps[group_id] == self.max_num_steps[group_id]:
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self._free_seq(seq)
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continue
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# Update the serving states.
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serving: List[SequenceGroup] = []
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for seq_group in self.serving:
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if seq_group.num_seqs(status=SequenceStatus.RUNNING) == 0:
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del self.num_steps[seq_group.group_id]
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del self.max_num_steps[seq_group.group_id]
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del self.stop_token_ids[seq_group.group_id]
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# TODO: Return the seq_group to the client.
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else:
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serving.append(seq_group)
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self.serving = serving
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